Painful temporomandibular muscle and joint disorders (TMJD) are the second most common musculoskeletal condition, affecting approximately 30 million Americans with an estimated annual cost of $4 billion. For the general dentist, diagnosing TMJD patients is challenging because the physical TMJD pain diagnoses lack prognostic value - unlike psychosocial TMJD factors, which are informative for treatment selection and as outcome predictors. However, the psychosocial assessment for TMJD is not routinely, if ever, used by the general dentist, who instead relies primarily on physical TMJD examination. Therefore, TMJD pain diagnoses need to have better clinical utility to improve the general dentist's triaging of more complex patients for specialty care. The central research hypothesis of this application is that the current physical TMJD pain assessment contains unused but valuable geographic TMJD pain information that correlates well with the psychosocial distress associated with TMJD. Using this information would produce a more informative TMJD pain diagnosis and consequently reduce the additional value of psychosocial assessment of TMJD patients. TMJD affect several locations in the jaw, joint, and temple, but often dental, oral, ear, neck, and head pains are also associated. Accordingly, TMJD pain has a location and distribution component; in fact, not all pain sites have equal importance for treatment outcomes, and a wider distribution of pain sites predicts unfavorable outcomes. Currently, even if this geographic pain information is collected during the diagnostic process, it is not incorporated into the diagnosis except for distinguishing between the TMJ versus muscle location of the pain. This study's objective is to improve existing TMJD pain diagnoses by integrating available information about the location and distribution of TMJD pain and testing whether these improved diagnoses are superior to existing ones in predicting psychosocial distress. Using the most widely applied TMJD diagnostic system, the Research Diagnostic Criteria for TMJD, data from the recently completed multi-center RDC/TMJD Validation Project (633 TMJD cases, 91 control subjects) and 416 cases from two German centers provide a cost- effective opportunity for determining the contribution of pain geography information for TMJD diagnosis using an innovative methodological approach applying geographic information systems (GIS) analyses. The specific aims are: (i) to identify patterns of TMJD pain geography corresponding to new TMJD pain diagnoses using exploratory data analysis of TMJD pain location data; and (ii) to test whether patterns of TMJD pain geography predict measures of psychosocial distress better than existing TMJD pain diagnoses. This application is innovative because it conceptualizes TMJD as a geographic pain condition, applying sophisticated methods from geography and public health. This application is significant because the new TMJD pain diagnoses will provide general dentists with a simple screening tool using routinely collected TMJD pain geography data to identify patients with psychosocial distress and to avoid psychosocial assessment for those who do not need it.